1. What is Motor Cable Selection?

Motor cable selection is the process of determining the appropriate cross-sectional area of electrical cables for motor applications based on current, distance, and allowable voltage drop. Proper sizing ensures safe operation and prevents excessive voltage drop.

2. How Does the Calculator Work?

The calculator uses the cable size formula:

Where:

• \( Current \) — Motor current in amperes (A)
• \( Length \) — Cable run length in meters
• \( Correction Factor \) — Adjustment for temperature, grouping, etc.
• \( Voltage Drop \) — Maximum allowable voltage drop in volts (V)

Explanation: The formula calculates the minimum cable cross-sectional area (mm²) needed to maintain voltage drop within acceptable limits.

3. Importance of Proper Cable Sizing

Details: Correct cable sizing prevents overheating, ensures proper motor operation, maintains efficiency, and complies with electrical codes. Undersized cables can cause voltage drop issues and safety hazards.

4. Using the Calculator

Tips:

• Enter motor full-load current in amperes
• Measure total cable length (both ways for AC circuits)
• Typical correction factor is 1.0 for standard conditions
• Common voltage drop limits: 3% for branch circuits, 5% for feeders

5. Frequently Asked Questions (FAQ)

Q1: What is a typical correction factor?
A: Standard is 1.0. Higher values account for multiple cables, high ambient temperature, or installation methods.

Q2: How do I determine allowable voltage drop?
A: Typically 3-5% of supply voltage. For 230V systems, 3% is 6.9V, 5% is 11.5V.

Q3: Should I round up cable sizes?
A: Yes, always select the next standard cable size above the calculated value.

Q4: Does this account for starting current?
A: No, this is for continuous operation. Motors with high starting current may need larger cables.

Q5: What about three-phase systems?
A: For three-phase, multiply the result by √3 (approximately 1.732).